The present invention is related to a heat-dissipating device, and especially to a composite heat-dissipating device constructed by a plurality of impellers, each of which has a plurality of blades, for enhancing the heat-dissipating performance.
Generally, in order to prevent the electronic device from being contaminated by particle or dust in the atmosphere, the electronic device is usually disposed in a closed housing. However, the electronic device will generate a lot of heat during the operating process. If the electronic device is continuously placed in a high-temperature state, it will easily cause a damage on the electronic device and shorten its useful life. Thus, in order to prevent the malfunction of the electronic device, a heat-dissipating fan is usually used to dissipate the heat generated by the electronic device from inside to external environment.
At the present time, a commonly used way for increasing the airflow discharged from the fan so as to enhance the heat-dissipating efficiency is to enlarge the size of blades of the fan or increase the number of blades. However, under the design limitation of mold used for manufacturing the fan, the size or number of blades of the fan can not be effectively increased to improve the heat-dissipating performance of the fan.
With the improvement of technology, one design is to allow two blades to be disposed closely as possible so as to slightly increase the discharged airflow. However, this way will let the mold have an acute notch as an edge on a knife, which may be vulnerable or easily damaged.
Therefore, it is desirable to provide a heat-dissipating device which can greatly enhance the heat-dissipating efficiency.
An object of the present invention is to provide a composite heat-dissipating device constructed by a plurality of impellers, each of which includes a plurality of blades. When the plurality of impellers are assembled together, the plurality of blades are arranged around the hub of the composite heat-dissipating device and there is an overlapped region formed between every two adjacent blades. Through such a design, it can significantly increase the number and size of blades so as to enhance the heat-dissipating performance.
Another object of the present invention is to provide a composite heat-dissipating device constructed by a plurality of impellers, each of which includes a plurality of blades. After the plurality of impellers are assembled together, all blades are arranged around the central hub of the composite heat-dissipating device. Because the size of the hub is circular, the size of blades can be precisely controlled so that the airflow field will not be affected and the heat-dissipating efficiency can be enhanced.
According to one aspect of the present invention, a first impeller of the plurality of impellers has a body and the plurality of blades are spacedly arranged around the body, and a second impeller of the plurality of impellers has a central part and the plurality of blades thereof are specedly arranged around the central part. When the first and second impellers are assembled together, the body of the first impeller and the central part of the second impeller are engaged together to constitute a hub of the composite heat-dissipating device, and the plurality of blades of the first and second impellers are alternately arranged around the hub.
In addition, the body of the first impeller has an engaging member located on an edge thereof, and the central part of the second impeller has a corresponding engaging member positioned on an edge thereof to be engaged with the engaging member of the first impeller.
Preferably, the body of the first impeller and the central part of the second impeller have rugged peripheries, respectively, which can be engaged with each other.
According to another aspect of the present invention, when the first and second impellers are assembled together, each blade of the first impeller is correspondingly engaged with that of the second impeller to constitute a complete blade of the composite heat-dissipating device, respectively. The proportion of each blade of the first impeller to the complete blade of the composite heat-dissipating device can be equal or unequal to that of each blade of the second impeller to the complete blade of the composite heat-dissipating device. Certainly, the engagement between each pair of the blades of the first and second impellers have optionally geometrical shapes which are able to be engaged with each other.
In addition, each of the plurality of blades is one selected from a group essentially consisting of inclined plate, triangle, trapezoid, curved, arcuate and wing structures.
The present invention may best be understood through the following description with reference to the accompanying drawings, in which: